Are the s&p 500 and world etf’s like IWDA overpriced?

Are the s&p 500 and world etf's like IWDA overpriced? Might be an ignorant question, but when an extremely large amount of people just blindly buy a world etf or something like the s&p 500 (like people currentlly do), wouldnt those companies in them be overpriced? And could it be possible that a portion of these great returns they have, is just the constant growing hype of these etf's? Or does the market self correct, like when a company in the s&p goes up because of hype, professional investors stop buying(immediatly correcting itself)? Sorry if this question is stupid or asked a lot, but everything i see when i search this on the internet is just thousand pages explaining what the s&p is :/